Process for preparing arylaminopropanols

ABSTRACT

The invention relates to a process for preparing enantiomerically enriched aryl-aminopropanols and to their use and also to intermediates.

This application is a division of U.S. Ser. No. 11/436,874, filed May 18, 2006, allowed; which is a division of U.S. Ser. No. 10/391,348, filed Mar. 18, 2003, now U.S. Pat. No. 7,169,938; which claims foreign priority of German Patent Application 102 12 301.2, filed Mar. 20, 2002.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The invention relates to a process for preparing enantiomerically enriched aryl-amino-propanols and to their use and also to intermediates.

2. Description of Related Art

1-Aryl-3-aminopropan-1-ols have gained industrial significance in particular as intermediates for the preparation of pharmaceuticals. For example, some 1-aryl-3-aminopropan-1-ols serve as precursor substances for the preparation of seratonin or noradrenalin takeup inhibitors. In the case of some of these inhibitors, it could be proven that certain enantiomers are not only inactive or less active, but may also even exhibit undesired side effects (U.S. Pat. No. 5,104,899).

Corey and Reichard (Tetrahedron Letters, 39, 5207, 1989) describe a process for preparing S-fluoxetine in which, in an important step, 3-chloropropiophenone is asymmetrically reduced using a chiral borane to give S-3-chloro-1-phenyl-1-propanol.

After reaction with sodium iodide and methylamine, (S)-3-(methylamino)-1-phenylpropan-1-ol is then obtained which may then be reacted further to the end product. Disadvantages of this process are that expensive reagents have to be used, and that the overall yield is only 77 to 82%.

A process for preparing enantiomerically enriched (1S)-3-(methylamino)-1-(2-thiophen-yl)-1-propanol starting from 1-(2-thiophen-yl)-3-chloropropan-1-one is described in Chirality 2000, 12, 26-29. After the reduction to racemic 3-chloro-1-(2-thienyl)-1-propanol, the racemate is enzymatically separated and the (S)-enantiomer is further reacted with NaI and methylamine to give (S)-3-(methylamino)-1-(2-thiophen-yl)-propan-1-ol. This method has the disadvantage that enzymatic racemate separations can in principle only provide 50% of the desired enantiomer and the overall yield is therefore economically unacceptable.

A similar synthetic route is described in J. Lab. Comp. Radiopharm. 1995, 36, 213-223, in which 1-(2-thiophen-yl)-3-chloropropan-1-one is asymmetrically reduced with borane and an oxazaborolidine. The yield in this step is only 61%, which makes the overall process uneconomic.

There was therefore a need for an efficient and widely applicable process for preparing enantiomerically enriched arylaminopropanols which starts from reactants obtainable in a simple manner.

SUMMARY OF THE INVENTION

A process has now been found for preparing enantiomerically enriched compounds of the formula (I) Ar—CH(OH)—CH₂—CH₂—NR¹R²   (I) where

-   Ar is a substituted or unsubstituted aryl radical and -   R¹ and R² are each independently hydrogen, C₁-C₂₀-alkyl, C₄-C₁₄-aryl     or C₅-C₁₅-arylalkyl, or the two R¹ and R² radicals together are     C₃-C₁₂-alkylene,     characterized in that -   a) compounds of the formula (II) are converted to enantiomerically     enriched compounds of the formula (III) or compounds of the     formula (IV) are converted to enantiomerically enriched compounds of     the formula (V)     Ar—CO—CH₂—COOR³   (II)     Ar—CH(OH)—CH₂—COOR³   (III)     Ar—CO—CH₂—CONR¹R²   (IV)     Ar—CH(OH)—CH₂—CONR¹R²   (V)     -   where, in each case,     -   Ar is as defined under the formula (I) and     -   R¹ and R² are each as defined under the formula (I) and     -   R³ is hydrogen, C₁-C₂₀-alkyl, C₄-C₁₄-aryl or C₅-C₁₅-arylalkyl,         and where the reaction is effected     -   in the presence of a transition metal catalyst     -   with hydrogen or a hydrogen-transferring compound or a mixture         thereof and -   b) in the case that compounds of the formula (II) have been used for     step a), the enantiomerically enriched compounds of the     formula (III) are reacted with amines of the formula (VI)     HNR¹R²   (VI)     -   where R¹ and R² are each as defined under the formula (I) to         give enantiomerically enriched compounds of the formula (V) as         defined above and -   c) the enantiomerically enriched compounds of the formula (V) are     converted by reduction to enantiomerically enriched compounds of the     formula (I) as defined above.

It is pointed out that the scope of the invention also encompasses any desired combinations of the ranges and areas of preference specified for each feature.

For the purposes of the invention, enantiomerically enriched refers to enantiomerically pure compounds or mixtures of enantiomers of a compound in which one enantiomer is present in an enantiomeric excess, also referred to hereinbelow as ee (enantiomeric excess), in comparison to the other enantiomer. This enantiomeric excess is preferably 10 to 100% ee, particularly preferably 60 to 100% ee and very particularly preferably 85 to 100% ee.

For the purposes of the invention, enantiomerically enriched relates in particular to the configuration of the carbon which is adjacent to the Ar radical.

DETAILED DESCRIPTION OF THE INVENTION

In the formulae (I) to (V), Ar is preferably a carbocyclic aromatic radical having 6 to 24 framework carbon atoms or a heteroaromatic radical having 4 to 24 framework carbon atoms in which no, one, two or three framework carbon atoms per cycle, but at least one framework carbon atom in the entire heteroaromatic radical, may be substituted by heteroatoms selected from the group of nitrogen, sulphur or oxygen.

The carbocyclic aromatic radicals or heteroaromatic radicals may also be substituted by up to five identical or different substituents per cycle selected from the group of hydroxyl, fluoro, nitro, cyano, free or protected formyl, C₁-C₁₂-alkyl, C₁-C₁₂-haloalkyl, C₅-C₁₄-aryl, C₆-C₁₅-arylalkyl, —PO—[(C₁-C₈)-alkyl]₂, —PO—[(C₅-C₁₄)-aryl]₂, —PO—[(C₁-C₈)-alkyl)(C₅-C₁₄)-aryl)], tri(C₁-C₈-alkyl)siloxyl or a radical of the general formula (VII) A-B-D-E  (VII) where, each independently,

-   A is missing or is a C₁-C₈-alkylene radical and -   B is missing or is oxygen, sulphur or NR⁴,     -   where R⁴ is hydrogen, C₁-C₈-alkyl, C₆-C₁₅-arylalkyl or         C₅-C₁₄-aryl and -   D is a carbonyl group and -   E is R⁵, OR⁵, NHR⁶ or N(R⁶)₂,     -   where R⁵ is C₁-C₈-alkyl, C₆-C₁₅-arylalkyl, C₁-C₈-haloalkyl or         C₅-C₁₄-aryl and     -   R⁶ is in each case independently C₁-C₈-alkyl, C₆-C₁₅-arylalkyl         or C₆-C₁₄-aryl, or N(R⁶)₂ together is a cyclic amino radical,         or a radical of the general formulae (VIIIa-e)         A-E  (VIIIa)         A-SO₂-E  (VIIIb)         A-B-SO₂R²   (VIIIc)         A-SO₃W   (VIIId)         A-COW  (VIIIe)         where A, B, E and R² are each as defined above and W is OH, NH₂         or OM where M is an alkali metal ion, half an equivalent of an         alkaline earth metal ion, an ammonium ion or an organic ammonium         ion.

Particularly preferably, in the formulae (I) to (V) Ar is a monocyclic or bicyclic carbocyclic aromatic radical having a total of 6 to 14 framework carbon atoms or a mono- or bicyclic heteroaromatic radical having 4 to 12 framework carbon atoms in which no, one, two or three framework carbon atoms per cycle, but at least one framework carbon atom in the entire heteroaromatic radical, may be substituted by heteroatoms selected from the group of nitrogen, sulphur or oxygen, and where the mono- or bicyclic aromatic radical may be substituted by no, one, two or three radicals per cycle, each of which is independently selected from the group of hydroxyl, C₁-C₁₂-alkyl, cyano, COOH, COOM, COO—(C₁-C₁₂-alkyl), COO—(C₄-C₁₀-aryl), CO—(C₁-C₁₂-alkyl), CO—(C₄-C₁₀-aryl), O—(C₁-C₁₂-alkyl), (C₁-C₁₂-alkyl)-O—(C₁-C₁₂-alkyl), (C₄-C₁₀-aryl)-O—(C₁-C₁₂-alkyl), O—(C₄-C₁₀-aryl), O—CO—(C₄-C₁₀-aryl), O—CO—(C₁-C₁₂-alkyl), OCOO—(C₁-C₁₂-alkyl), N—(C₁-C₁₂-alkyl)₂, NH—(C₁-C₁₂-alkyl), N(C₄-C₁₀-aryl)₂, NH—(C₄-C₁₀-aryl), fluorine, chlorine, bromine, NO₂, SO₃H, SO₃M, SO₂(C₁-C₁₂-alkyl), SO(C₁-C₁₂-alkyl), C₁-C₁₂-fluoroalkyl where fluoroalkyl is a singly, multiply or fully fluorine-substituted alkyl radical as defined above, NHCO—(C₁-C₁₂-alkyl), CONH₂, CONH—(C₁-C₁₂-alkyl), NHCOO—(C₁-C₁₂-alkyl), PO(C₄-C₁₀-aryl)₂, PO(C₁-C₁₂-alkyl)₂, PO₃H₂, PO₃M₂, PO₃HM, PO(O(C₁-C₁₂-alkyl)₂ where M is in each case an alkali metal ion or half an equivalent of an alkaline earth metal ion.

Very particularly preferably, aryl is phenyl, 2- or 3-thiophenyl, 2- or 3-furanyl, 2- or 3-pyrrolyl, 3- or 4-pyrazolyl, 1-, 2-, or 4-thiazolyl, 1-, 2-, or 4-oxazolyl, 2-, 4- or 5-imidazolyl, 2-, 3-, or 4-pyridyl, 2- or 3-pyrazinyl, 2-, 4-, or 5-pyrimidyl, 3-, 4-, 5- or 6-pyridazinyl, 2- or 3-indolyl, 3-indazolyl, indazolyl, 2- or 3-benzofuranyl, 2- or 3-benzothiophen-yl, 2-, 3- or 4-quinolinyl, isoquinolinyl 2-, 4-, 6- or 7-pteridinyl or 2-, 3-, 4-, 5-, 6-, 8-, 9- or 10-phenanthrenyl where each of the radicals mentioned bears no, one or two radicals per cycle, each of which is independently selected from the group of C₁-C₄-alkyl, cyano, COO—(C₁-C₄-alkyl), O—(C₁-C₄-alkyl), N(C₁-C₄-alkyl)₂, NH—(C₁-C₄-alkyl), fluorine, chlorine, bromine or C₁-C₄-fluoroalkyl, for example trifluoromethyl, 2,2,2-trifluoroethyl or pentafluoroethyl.

Even greater preference is given to Ar being 2-thiophen-yl.

R¹ and R² in the formulae (I), (IV), (V) and (VI) are preferably each independently hydrogen, methyl, ethyl, isopropyl, phenyl or benzyl.

NR¹R² as a whole in the formulae (I), (IV) and (V) is particularly preferably methylamino, ethylamino and isopropylamino, and, in formula (VI), HNR¹R² is methylamine, ethylamine and isopropylamine.

NR¹R² as whole in the formulae (I), (IV) and (V) is very particularly preferably methylamino, and, in formula (VI), HNR¹R² is methylamine.

R³ in the formulae (II) and (III) is in each case preferably hydrogen, methyl, ethyl, isopropyl, n-propyl, tert-butyl, n-butyl, isobutyl, phenyl or benzyl, although particular preference is given to methyl and ethyl, and very particular preference to methyl.

Preferred compounds of the formula (II) for the process according to the invention are: methyl 3-oxo-3-(2-thienyl)propanoate, ethyl 3-oxo-3-(2-thienyl)propanoate, isopropyl 3-oxo-3-(2-thienyl)propanoate, tert-butyl 3-oxo-3-(2-thienyl)propanoate, 2-ethylhexyl 3-oxo-3-(2-thienyl)propanoate, methyl 3-oxo-3-(phenyl)propanoate, ethyl 3-oxo-3-(phenyl)propanoate, isopropyl 3-oxo-3-(phenyl)propanoate, tert-butyl 3-oxo-3-(phenyl)propanoate, 2-ethylhexyl 3-oxo-3-(phenyl)propanoate, methyl 3-oxo-3-(4-tolyl)propanoate, ethyl 3-oxo-3-(4-tolyl)propanoate, isopropyl 3-oxo-3-(4-tolyl)propanoate, tert-butyl 3-oxo-3-(4-tolyl)propanoate and 2-ethylhexyl 3-oxo-3-(4-tolyl)propanoate.

Preferred compounds of the formula (IV) for the process according to the invention are: 3-oxo-3-(phenyl)propanamide, N-methyl-3-oxo-3-(phenyl)propanamide, N-benzyl-3-oxo-3-(phenyl)propanamide, N,N-dimethyl-3-oxo-3-(phenyl)propanamide, 3-oxo-3-(4-tolyl)propanamide, N-methyl-3-oxo-3-(4-tolyl)propanamide, N-benzyl-3-oxo-3-(4-tolyl)propanamide, N,N-dimethyl-3-oxo-3-(4-tolyl)propanamide, 3-oxo-3-(2-thienyl)propanamide, N-methyl-3-oxo-3-(2-thienyl)propanamide and N-benzyl-3-oxo-3-(2-thienyl)propanamide.

For the process according to the invention, preference is given to using compounds of the formula (II) in step a) having the definitions and areas of preference specified above.

For the process according to the invention, particular preference is given to using compounds of the formula (II) in step a) having the definitions and areas of preference specified above for Ar and R¹ and, in step b), to reacting with methylamine.

The compounds of the formula (II) which can be used for the process according to the invention may be obtained, for example, by reacting compounds of the formula (IX) Ar—CO—CH₃   (IX)

-   where Ar has the same definition and areas of preference specified     under the formula (I) with compounds of the formula (X)     R³—O—CO—OR³   (X) -   where the R³ radicals each independently have the same definition     and areas of preference as stated under the formula (II).

An example is the reaction of 2-acetylthiophene with dimethyl carbonate, diethyl carbonate, diphenyl carbonate or dibenzyl carbonate.

The compounds of the formula (IV) which can be used for the process according to the invention may be obtained in a similar manner to the compounds of the formula (II), for example, by base-catalysed reaction of compounds of the formula (IX) with compounds of the formula (XI) R³—O—CO—NR¹R²   (XI) where R¹, R² and R³ radicals each independently, but preferably identically, have the same definition and areas of preference as stated under the formulae (II) and (IV).

Examples of compounds of the formula (XI) include:

-   methyl N-methylcarbamate, ethyl N-methylcarbamate, methyl     N-methylcarbamate, ethyl N-methylcarbamate, methyl     N,N-dimethylcarbamate and ethyl N,N-dimethyl-carbamate.

Such a reaction is described, for example, in Tetrahedron Lett. 1998, 39, 4995 and may, for example, be applied in a similar manner for the reaction of 2-acetylthiophene with methyl N-methylcarbamate or ethyl N-methylcarbamate.

The compounds of the formula (IV) which can be used for the process according to the invention may likewise be obtained via a base-catalysed reaction of the compounds of the general formula (IX) with isocyanates, as described in Synth. Commun. 1987, 17, 13-18. An example is the reaction of 2-acetylthiophene with methyl isocyanate, ethyl isocyanate or benzyl isocyanate.

For the purposes of the invention, aryl is, for example and with preference, a carbocyclic aromatic radical or heteroaromatic radical which contains no, one, two or three heteroatoms per cycle, but at least one heteroatom in the entire heteroaromatic radical, which are selected from the group of nitrogen, sulphur or oxygen. The carbocyclic aromatic radicals or heteroaromatic radicals may also be substituted by up to five substituents per cycle, each of which is independently, for example and with preference, selected from the group of hydroxyl, C₁-C₁₂-alkyl, cyano, COOH, COOM where M is an alkali metal ion or half an equivalent of an alkaline earth metal ion, COO—(C₁-C₁₂-alkyl), COO—(C₄-C₁₀-aryl), CO—(C₁-C₁₂-alkyl), CO—(C₄-C₁₀-aryl), O—(C₁-C₁₂-alkyl), O—(C₄-C₁₀-aryl, N(C₁-C₁₂-alkyl)₂, NH—(C₁-C₁₂-alkyl), fluorine, chlorine, bromine, C₁-C₁₂-fluoroalkyl where fluoroalkyl is a singly, multiply or fully fluorine-substituted alkyl radical as defined above, CONH₂, CONH—(C₁-C₁₂-alkyl), NHCOO—(C₁-C₁₂-alkyl). The same applies to the aryl moiety of an arylalkyl radical.

For the purposes of the invention, alkyl or alkylene or alkoxy is in each case independently a straight-chain, cyclic, branched or unbranched alkyl or alkylene or alkoxy radical which may optionally be further substituted by C₁-C₄-alkoxy radicals. The same applies to the alkylene moiety of an arylalkyl radical.

In all contexts, C₁-C₆-alkyl is, for example, methyl, ethyl, n-propyl, isopropyl, n-butyl, tert-butyl, n-pentyl, cyclohexyl and n-hexyl, C₁-C₈-alkyl is additionally, for example, n-heptyl, n-octyl or isooctyl, C₁-C₁₂-alkyl is further additionally, for example, n-decyl and n-dodecyl, and C₁-C₂₀-alkyl is still further additionally n-hexadecyl and n-octadecyl.

For example, C₁-C₄-alkylene in all contexts is preferably methylene, 1,1-ethylene, 1,2-ethylene, 1,1-propylene, 1,2-propylene, 1,3-propylene, 1,1-butylene, 1,2-butylene, 2,3-butylene and 1,4-butylene, and C₁-C₈-alkylene is additionally 1,5-pentylene, 1,6-hexylene, 1,1-cyclohexylene, 1,4-cyclohexylene, 1,2-cyclohexylene and 1,8-octylene.

For example, C₁-C₄-alkoxy in all contexts is preferably methoxy, ethoxy, isopropoxy, n-propoxy, n-butoxy and tert-butoxy, and C₁-C₈-alkoxy is additionally cyclohexyloxy. The general term aryl as a substituent encompasses carbocyclic radicals and heteroaromatic radicals in which no, one, two or three framework atoms per cycle, but at least one framework atom in the entire radical, are heteroatoms selected from the group of nitrogen, sulphur or oxygen. C₅-C₁₀-Aryl is, for example and with preference, phenyl, pyridyl, o-, m- or p-tolyl, and C₅-C₁₄-aryl is additionally anthracenyl.

The same applies to the aryl moiety of an arylalkyl radical. C₆-C₁₅-Arylalkyl is, for example and with preference, benzyl.

For the purposes of the invention, haloalkyl and fluoroalkyl are each independently a straight-chain, cyclic, branched or unbranched alkyl radical which may be substituted by one or more, or fully by, halogen atoms independently selected from the group of fluorine, chlorine or bromine, and fluorine respectively.

For example and with preference, C₁-C₈-haloalkyl is in all contexts preferably trifluoromethyl, trichloromethyl, 2,2,2-trifluoroethyl, pentafluoroethyl and nonafluorobutyl and C₁-C₈-fluoroalkyl is trifluoromethyl, 2,2,2-trifluoroethyl, pentafluoroethyl and nonafluorobutyl.

Protected formyl means a formyl radical which is protected by converting to aminal, acetal or a mixed aminalacetal where the aminals, acetals and mixed aminalacetals may be acyclic or cyclic.

For example and with preference, protected formyl is a 1,1-(2,5-dioxy)cyclopentylene radical.

In step a) of the process according to the invention, the compounds of the formula (II) are converted in the presence of a transition metal catalyst to enantiomerically enriched compounds of the formula (III), or compounds of the formula (IV) are converted to enantiomerically enriched compounds of the formula (V), and the reaction is effected with hydrogen or a hydrogen-transferring compound or a mixture thereof.

The catalytic reduction of ketones to enantiomerically enriched secondary alcohols is known in principle. The reducing agents used are customarily molecular hydrogen or, in the case of transfer hydrogenations, hydrogen-transferring compounds, for example formic acid or isopropanol.

Step a) may be carried out, for example and with preference, in such a way that the compounds of the formula (II) or the compounds of the formula (IV) are reduced by hydrogen in the presence of transition metal catalysts and optionally solvents which comprise chiral, stereoisomerically enriched ruthenium, rhodium, iridium or palladium complexes, or are obtained by reacting ruthenium, rhodium, iridium or palladium salts with stereoisomerically enriched ligands.

For example, the asymmetric hydrogenation of aryl β-ketoesters using Ru-phosphine catalysts is described in Tetrahedron 1995, 27, 4801 or Org. and Organomet. Synth. 1999, 2, 175. An overview article can be found in Tetrahedron Asymmetry 1997, 8, 3327. Ruthenium catalysts having binaphthyl or biphenylphosphine ligands are suitable in particular for the asymmetric hydrogenation, as described in EP 529444, EP 643 065, EP 749 973 and EP 764 652.

However, for the process according to the invention, preference is given to carrying out step a) as a transfer hydrogenation.

In a preferred embodiment, step a) is carried out in such a way that the compounds of the formula (II) or the compounds of the formula (IV) are reacted

-   i) in the presence of a ruthenium-, rhodium- or iridium-containing     catalyst and -   ii) in the presence of at least one amine, at least some of which is     present in protonated form, -   iii) with formic acid, formate or mixtures thereof. -   iv) optionally in the presence of organic solvent.

For example and with preference, the catalysts used are those which comprise ruthenium complexes. Preferred ruthenium complexes are those which are obtainable by reacting compounds of the formula (XII) with compounds of the formula (XIII), or complexes of the formula (XIV). Particular preference is given to using those ruthenium complexes which are obtainable by reacting compounds of the formula (XII) with compounds of the formula (XIII). In a preferred embodiment, the molar ratio of compounds of the formula (XIII) to compounds of the formula (II) is 2:1 to 3:1, particularly preferably 2.01:1 to 2.4:1.

Advantageously, compounds of the formula (XIII) and compounds of the formula (XII) are mixed and the mixture is taken up in organic solvent. The resulting mixture may also, before addition to the reaction mixture, advantageously be stirred with a base, preferably a tertiary amine and, for example and with preference, for 10 to 30 min, and the molar amount of tertiary amine is, for example and with preference, 1:1 to 3:1, more preferably 1:1 to 2:1, based on compounds of the formula (XIII).

For organic solvents and amines, the same statements and areas of preference apply as will be described in detail below.

In the compounds of the formula (XII) [RuX₂(arene)]₂   (XII),

-   arene is a coordinated aromatic compound having 6 to 12 ring carbon     atoms which may be further substituted by up to 6 radicals, each of     which is independently selected from the group of C₁-C₈-alkyl,     benzyl and phenyl and -   X is, for example and with preference, chlorine, bromine or iodine,     particularly preferably chlorine.

Arene is preferably benzene or naphthalene which may be substituted by up to 6 radicals, each of which is independently selected from the group of methyl, ethyl, n-propyl, isopropyl and tert-butyl.

Arene is preferably mesitylene, cumene or benzene.

Particularly preferred compounds of the formula (XII) are: (benzene)dichlororuthenium dimer, (mesitylene)dichlororuthenium dimer and (cumene)dichlororuthenium dimer, and even greater preference is given to (cumene)dichlororuthenium dimer.

In the formula (XIII)

-   R⁷ and R⁸ are each independently, for example, C₁-C₂₀-alkyl,     C₄-C₁₅-aryl or C₅-C₁₆-arylalkyl, or R⁷ and R⁸ together are a     straight-chain or branched C₃-C₁₂-alkylene radical, and -   R⁹ is C₁-C₂₀-alkyl, C₁-C₂₀-fluoroalkyl or C₄-C₁₅-aryl.

R⁷ and R⁸ are preferably identically phenyl or are together straight-chain C₃-C₈-alkylene, for example 1,3-propylene or 1,4-butylene, and R⁷ and R⁸ are particularly preferably identically phenyl.

-   R⁹ is preferably C₁-C₄-alkyl, C₁-C₄-fluoroalkyl, phenyl or naphthyl     which may be further substituted by no, one, two, three, four or     five radicals which are selected from the group of C₁-C₄-alkyl,     C₁-C₄-alkoxy, C₁-C₄-fluoroalkyl, fluorine and chlorine. -   R⁹ is particularly preferably methyl, trifluoromethyl,     pentafluoroethyl, nona-fluorobutyl, phenyl, p-tolyl, p-ethylphenyl,     p-anisyl, p-ethoxyphenyl, p-chlorophenyl, 2,4,6-trimethylphenyl,     2,4,6-triisopropylphenyl, p-fluorophenyl, pentafluorophenyl and     naphthyl. -   R⁹ is very particularly preferably p-tolyl, phenyl, naphthyl. -   R⁹ is even more preferably p-tolyl.

The compounds of the formula (XIII) preferably had a stereoisomeric purity of 90% or more, particularly preferably 95% or more and very particularly preferably 98.5% or more.

Examples of compounds of the formula (XIII) include:

-   N-[(1R,2R) and     (1S,2S)-2-amino-1,2-diphenylethyl]-p-tolylsulphonamide, N[(1R,2R)     and (1S,2S)-2-amino-1,2-diphenylethyl]-o-tolylsulphonamide,     N-[(1R,2R) and     (1S,2S)-2-amino-1,2-diphenylethyl]-m-tolylsulphonamide, N-[(1R,2R)     and (1S,2S)-2-amino-1,2-diphenylethyl]-phenylsulphonamide,     N-[(1R,2R) and     (1S,2S)-2-amino-1,2-diphenylethyl]-4-ethylphenylsulphonamide,     N-[(1R,2R) and     (1S,2S)-2-amino-1,2-diphenylethyl]-3-ethylphenylsulphonamide,     N-[(1R,2R) and     (1S,2S)-2-amino-1,2-diphenylethyl]-2-ethylphenylsulphonamide,     N-[(1R,2R) and     (1S,2S)-2-amino-1,2-diphenylethyl]-2,4,6-trimethylphenylsulphonamide,     N-[(1R,2R) and     (1S,2S)-2-amino-1,2-diphenylethyl]-2,4,6-triisopropylphenylsulphonamide,     N-[(1R,2R) and     (1S,2S)-2-amino-1,2-diphenylethyl]-4-chlorophenylsulphonamide,     N-[(1R,2R) and     (1S,2S)-2-amino-1,2-diphenylethyl]-3-chlorophenylsulphonamide,     N-[(1R,2R) and     (1S,2S)-2-amino-1,2-diphenylethyl]-2-chlorophenylsulphonamide,     N-[(1R,2R) and     (1S,2S)-2-amino-1,2-diphenylethyl]-4-fluorophenylsulphonamide,     N-[(1R,2R) and     (1S,2S)-2-amino-1,2-diphenylethyl]-3-fluorophenylsulphonamide,     N-[(1R,2R) and     (1S,2S)-2-amino-1,2-diphenylethyl]-2-fluorophenylsulphonamide,     N-[(1R,2R) and     (1S,2S)-2-amino-1,2-diphenylethyl]-4-methoxyphenylsulphonamide,     N-[(1R,2R) and     (1S,2S)-2-amino-1,2-diphenylethyl]-3-methoxyphenylsulphonamide,     N-[(1R,2R) and     (1S,2S)-2-amino-1,2-diphenylethyl]-2-methoxyphenylsulphonamide,     N-[(1R,2R) and     (1S,2S)-2-amino-1,2-diphenylethyl]-1-naphthylsulphonamide,     N-[(1R,2R) and     (1S,2S)-2-amino-1,2-diphenylethyl]-2-naphthylsulphonamide,     N-[(1R,2R) and     (1S,2S)-2-amino-1,2-diphenylethyl]-pentafluorophenylsulphonamide,     N-[(1R,2R) and     (1S,2S)-2-amino-1,2-diphenylethyl]-methanesulphonamide, N-[(1R,2R)     and (1S,2S)-2-amino-1,2-diphenylethyl]-trifluoromethanesulphonamide,     N-[(1R,2R) and (1S,2S)-2-aminocyclohexyl]-p-tolylsulphonamide,     N-[(1R,2R) and (1S,2S)-2-aminocyclohexyl]-o-tolylsulphonamide,     N-[(1R,2R) and (1S,2S)-2-aminocyclohexyl]-m-tolylsulphonamide,     N-[(1R,2R) and (1S,2S)-2-aminocyclohexyl]-phenylsulphonamide,     N-[(1R,2R) and (1S,2S)-2-aminocyclohexyl]-4-ethylphenylsulphonamide,     N-[(1R,2R) and (1S,2S)-2-aminocyclohexyl]-3-ethylphenylsulphonamide,     N-[(1R,2R) and (1S,2S)-2-aminocyclohexyl]-2-ethylphenylsulphonamide,     N-[(1R,2R) and     (1S,2S)-2-aminocyclohexyl]-2,4,6-trimethylphenylsulphonamide,     N-[(1R,2R) and     (1S,2S)-2-aminocyclohexyl]-2,4,6-triisopropylphenylsulphonamide,     N-[(1R,2R) and     (1S,2S)-2-aminocyclohexyl]-4-chlorophenylsulphonamide, N-[(1R,2R)     and (1S,2S)-2-aminocyclohexyl]-3-chlorophenylsulphonamide,     N-[(1R,2R) and     (1S,2S)-2-aminocyclohexyl]-2-chlorophenylsulphonamide, N-[(1R,2R)     and (1S,2S)-2-aminocyclohexyl]-4-fluorophenylsulphonamide,     N-[(1R,2R) and     (1S,2S)-2-aminocyclohexyl]-3-fluorophenylsulphonamide, N-[(1R,2R)     and (1S,2S)-2-aminocyclohexyl]-2-fluorophenylsulphonamide,     N-[(1R,2R) and     (1S,2S)-2-aminocyclohexyl]-4-methoxyphenylsulphonamide, N-[(1R,2R)     and (1S,2S)-2-aminocyclohexyl]-3-methoxyphenylsulphonamide,     N-[(1R,2R) and     (1S,2S)-2-aminocyclohexyl]-2-methoxyphenylsulphonamide, N-[(1R,2R)     and (1S,2S)-2-aminocyclohexyl]-1-naphthylsulphonamide, N-[(1R,2R)     and (1S,2S)-2-aminocyclohexyl]-2-naphthylsulphon amide, N-[(1R,2R)     and (1S,2S)-2-aminocyclohexyl]-pentafluorophenylsulphonamide,     N-[(1R,2R) and (1S,2S)-2-aminocyclohexyl]-methanesulphonamide,     N-[(1R,2R) and     (1S,2S)-2-aminocyclohexyl]-trifluoromethanesulphonamide, N-[(1R,2R)     and (1S,2S)-2-aminocyclopentyl]-p-tolylsulphonamide, N-[(1R,2R) and     (1S,2S)-2-aminocyclopentyl]-o-tolylsulphonamide, N-[(1R,2R) and     (1S,2S)-2-aminocyclopentyl]-m-tolylsulphonamide, N-[(1R,2R) and     (1S,2S)-2-aminocyclopentyl]phenylsulphonamide, N-[(1R,2R) and     (1S,2S)-2-aminocyclopentyl]-4-ethylphenylsulphonamide, N-[(1R,2R)     and (1S,2S)-2-aminocyclopentyl]-3-ethylphenylsulphonamide,     N-[(1R,2R) and     (1S,2S)-2-aminocyclopentyl]-2-ethylphenylsulphonamide, N-[(1R,2R)     and (1S,2S)-2-aminocyclopentyl]-2,4,6-trimethylphenylsulphonamide,     N-[(1R,2R) and     (1S,2S)-2-aminocyclopentyl]-2,4,6-triisopropylphenylsulphonamide,     N-[(1R,2R) and     (1S,2S)-2-aminocyclopentyl]-4-chlorophenylsulphonamide, N-[(1R,2R)     and (1S,2S)-2-aminocyclopentyl]-3-chlorophenylsulphonamide,     N-[(1R,2R) and     (1S,2S)-2-aminocyclopentyl]-2-chlorophenylsulphonamide, N-[(1R,2R)     and (1S,2S)-2-aminocyclopentyl]-4-fluorophenylsulphonamide,     N-[(1R,2R) and     (1S,2S)-2-aminocyclopentyl]-3-fluorophenylsulphonamide, N-[(1R,2R)     and (1S,2S)-2-aminocyclopentyl]-2-fluorophenylsulphonamide,     N-[(1R,2R) and     (1S,2S)-2-aminocyclopentyl]-4-methoxyphenylsulphonamide, N-[(1R,2R)     and (1S,2S)-2-aminocyclopentyl]-3-methoxyphenylsulphonamide,     N-[(1R,2R) and     (1S,2S)-2-aminocyclopentyl]-2-methoxyphenylsulphonamide, N-[(1R,2R)     and (1S,2S)-2-aminocyclopentyl]-1-naphthylsulphonamide, N-[(1R,2R)     and (1S,2S)-2-aminocyclopentyl]-2-naphthylsulphonamide, N-[(1R,2R)     and (1S,2S)-2-aminocyclopentyl]-pentafluorophenylsulphonamide,     N-[(1R,2R) and (1S,2S)-2-aminocyclopentyl]-methanesulphonamide,     N-[(1R,2R) and     (1S,2S)-2-aminocyclopentyl]-trifluoromethanesulphonamide.

In the formula (XIV) [RuX₂(arene){(XIII) }]  (XIV), arene and X each have the definition and areas of preference specified under formula (XII), (XIII) in the formula (XIV) represents compounds of the formula (XIII) with the definitions and areas of preference specified there.

Compounds of the formula (XIV) include:

-   [N-[(1R,2R and     1S,2S)-2-(amino-κN)-1,2-diphenylethyl]-p-tolylsulphonamidato-κN]chloro[(η⁶)-cumene]ruthenium(II) -   [N-[(1R,2R and     1S,2S)-2-(amino-κN)-1,2-diphenylethyl]-o-tolylsulphonamidato-κN]chloro[(η⁶)-cumene]ruthenium(II) -   [N-[(1R,2R and     1S,2S)-2-(amino-κN)-1,2-diphenylethyl]-m-tolylsulphonamidato-κN]chloro[(η⁶)-cumene]ruthenium(II) -   [N-[(1R,2R and     1S,2S)-2-(amino-κN)-1,2-diphenylethyl]-phenylsulphonamidato-κN]chloro[(η⁶)-cumene]ruthenium(II) -   [N-[(1R,2R and     1S,2S)-2-(amino-κN)-1,2-diphenylethyl]-4-ethylphenylsulphonamidato-κN]chloro[(η⁶)-cumene]ruthenium(II) -   [N-[(1R,2R and     1S,2S)-2-(amino-κN)-1,2-diphenylethyl]-3-ethylphenylsulphonamidato-κN]chloro[(η⁶)-cumene]ruthenium(II) -   [N-[(1R,2R and     1S,2S)-2-(amino-κN)-1,2-diphenylethyl]-2-ethylphenylsulphonamidato-κN]chloro[(η⁶)-cumene]ruthenium(II) -   [N-[(1R,2R and     1S,2S)-2-(amino-κN)-1,2-diphenylethyl]-2,4,6-trimethylphenylsulphonamidato-κN]chloro[(η⁶)-cumene]ruthenium(II) -   [N-[(1R,2R and     1S,2S)-2-(amino-κN)-1,2-diphenylethyl]-2,4,6-triisopropylphenylsulphonamidato-κN]chloro[(η⁶)-cumene]ruthenium(II) -   [N-[(1R,2R and     1S,2S)-2-(amino-κN)-1,2-diphenylethyl]-4-chlorophenylsulphonamidato-κN]chloro[(η⁶)-cumene]ruthenium(II) -   [N-[(1R,2R and     1S,2S)-2-(amino-κN)-1,2-diphenylethyl]-3-chlorophenylsulphonamidato-κN]chloro[(η⁶)-cumene]ruthenium(II) -   [N-[(1R,2R and     1S,2S)-2-(amino-κN)-1,2-diphenylethyl]-2-chlorophenylsulphonamidato-κN]chloro[(η⁶)-cumene]ruthenium(II) -   [N-[(1R,2R and     1S,2S)-2-(amino-κN)-1,2-diphenylethyl]-4-fluorophenylsulphonamidato-κN]chloro[(η⁶)-cumene]ruthenium(II) -   [N-[(1R,2R and     1S,2S)-2-(amino-κN)-1,2-diphenylethyl]-3-fluorophenylsulphonamidato-κN]chloro[(η⁶)-cumene]ruthenium(II) -   [N-[(1R,2R and     1S,2S)-2-(amino-κN)-1,2-diphenylethyl]-2-fluorophenylsulphonamidato-κN]chloro[(η⁶)-cumene]ruthenium(II) -   [N-[(1R,2R and     1S,2S)-2-(amino-κN)-1,2-diphenylethyl]-4-methoxyphenylsulphonamidato-κN]chloro[(η⁶)-cumene]ruthenium(II) -   [N-[(1R,2R and     1S,2S)-2-(amino-κN)-1,2-diphenylethyl]-3-methoxyphenylsulphonamidato-κN]chloro[(η⁶)-cumene]ruthenium(II) -   [N-[(1R,2R and     1S,2S)-2-(amino-κN)-1,2-diphenylethyl]-2-methoxyphenylsulphonamidato-κN]chloro[(η⁶)-cumene]ruthenium(II)ato-κN]chloro[(η⁶)-cumene]-ruthenium(II) -   [N-[(1R,2R and     1S,2S)-2-(amino-κN)-1,2-diphenylethyl]-1-naphthylsulphonamidato-κN]chloro[(η⁶)-cumene]ruthenium(II) -   [N-[(1R,2R and     1S,2S)-2-(amino-κN)-1,2-diphenylethyl]-2-naphthylsulphonamidato-κN]chloro[(η⁶)-cumene]ruthenium(II) -   [N-[(1R,2R and     1S,2S)-2-(amino-κN)-1,2-diphenylethyl]-pentafluorophenylsulphonamidato-κN]chloro[(η⁶)-cumene]ruthenium(II) -   [N-[(1R,2R and     1S,2S)-2-(amino-κN)-1,2-diphenylethyl]-methanesulphonamidato-κN]chloro[(η⁶)-cumene]ruthenium(II) -   [N-[(1R,2R and     1S,2S)-2-(amino-κN)-1,2-diphenylethyl]-trifluoromethanesulphonamidato-κN]chloro[(η⁶)-cumene]ruthenium(II) -   [N-[(1R,2R and     1S,2S)-2-(amino-κN)-1,2-diphenylethyl]-p-tolylsulphonamidato-κN]chloro[(η⁶)-1,3,5-trimethylbenzene]ruthenium(II) -   [N-[(1R,2R and     1S,2S)-2-(amino-κN)-1,2-diphenylethyl]-o-tolylsulphonamidato-κN]chloro[(η⁶)-1,3,5-trimethylbenzene]ruthenium(II) -   [N-[(1R,2R and     1S,2S)-2-(amino-κN)-1,2-diphenylethyl]-m-tolylsulphonamidato-κN]chloro[(η⁶)-1,3,5-trimethylbenzene]ruthenium(II) -   [N-[(1R,2R and     1S,2S)-2-(amino-κN)-1,2-diphenylethyl]-phenylsulphonamidato-κN]chloro[(η⁶)-1,3,5-trimethylbenzene]ruthenium(II) -   [N-[(1R,2R and     1S,2S)-2-(amino-κN)-1,2-diphenylethyl]-4-ethylphenylsulphonamidato-κN]chloro[(η⁶)-1,3,5-trimethylbenzene]ruthenium(II) -   [N-[(1R,2R and     1S,2S)-2-(amino-κN)-1,2-diphenylethyl]-3-ethylphenylsulphonamidato-κN]chloro[(η⁶)-1,3,5-trimethylbenzene]ruthenium(II) -   [N-[(1R,2R and     1S,2S)-2-(amino-κN)-1,2-diphenylethyl]-2-ethylphenylsulphonamidato-κN]chloro[(η⁶)-1,3,5-trimethylbenzene]ruthenium(II) -   [N-[(1R,2R and     1S,2S)-2-(amino-κN)-1,2-diphenylethyl]-2,4,6-trimethylphenylsulphonamidato-κN]chloro[(η⁶)-1,3,5-trimethylbenzene]ruthenium(II) -   [N-[(1R,2R and     1S,2S)-2-(amino-κN)-1,2-diphenylethyl]-2,4,6-triisopropylphenylsulphonamidato-κN]chloro[(η⁶)-1,3,5-trimethylbenzene]ruthenium(II) -   [N-[(1R,2R and     1S,2S)-2-(amino-κN)-1,2-diphenylethyl]-4-chlorophenylsulphonamidato-κN]chloro[(η⁶)-1,3,5-trimethylbenzene]ruthenium(II) -   [N-[(1R,2R and     1S,2S)-2-(amino-κN)-1,2-diphenylethyl]-3-chlorophenylsulphonamidato-κN]chloro[(η⁶)-1,3,5-trimethylbenzene]ruthenium(II) -   [N-[(1R,2R and     1S,2S)-2-(amino-κN)-1,2-diphenylethyl]-2-chlorophenylsulphonamidato-κN]chloro[(η⁶)-1,3,5-trimethylbenzene]ruthenium(II) -   [N-[(1R,2R and     1S,2S)-2-(amino-κN)-1,2-diphenylethyl]-4-fluorophenylsulphonamidato-κN]chloro[(η⁶)-1,3,5-trimethylbenzene]ruthenium(II) -   [N-[(1R,2R and     1S,2S)-2-(amino-κN)-1,2-diphenylethyl]-3-fluorophenylsulphonamidato-κN]chloro[(η⁶)-1,3,5-trimethylbenzene]ruthenium(II) -   [N-[(1R,2R and     1S,2S)-2-(amino-κN)-1,2-diphenylethyl]-2-fluorophenylsulphonamidato-κN]chloro[(η⁶)-1,3,5-trimethylbenzene]ruthenium(II) -   [N-[(1R,2R and     1S,2S)-2-(amino-κN)-1,2-diphenylethyl]-4-methoxyphenylsulphonamidato-κN]chloro[(η⁶)-1,3,5-trimethylbenzene]ruthenium(II) -   [N-[(1R,2R and     1S,2S)-2-(amino-κN)-1,2-diphenylethyl]-3-methoxyphenylsulphonamidato-κN]chloro[(η⁶)-1,3,5-trimethylbenzene]ruthenium(II) -   [N-[(1R,2R and     1S,2S)-2-(amino-κN)-1,2-diphenylethyl]-2-methoxyphenylsulphonamidato-κN]chloro[(η⁶)-1,3,5-trimethylbenzene]ruthenium(II)ato-κN]chloro[(η⁶)-1,3,5-trimethylbenzene]ruthenium(II) -   [N-[(1R,2R and     1S,2S)-2-(amino-κN)-1,2-diphenylethyl]-1-naphthylsulphonamidato-κN]chloro[(η⁶)-1,3,5-trimethylbenzene]ruthenium(II) -   [N-[(1R,2R and     1S,2S)-2-(amino-κN)-1,2-diphenylethyl]-2-naphthylsulphonamidato-κN]chloro[(η⁶)-1,3,5-trimethylbenzene]ruthenium(II) -   [N-[(1R,2R and     1S,2S)-2-(amino-κN)-1,2-diphenylethyl]-pentafluorophenylsulphonamidato-κN]chloro[(η⁶)-1,3,5-trimethylbenzene]ruthenium(II) -   [N-[(1R,2R and     1S,2S)-2-(amino-κN)-1,2-diphenylethyl]-methanesulphonamidato-κN]chloro[(η⁶)-1,3,5-trimethylbenzene]ruthenium(II) -   [N-[(1R,2R and     1S,2S)-2-(amino-κN)-1,2-diphenylethyl]-trifluoromethanesulphonamidato-κN]chloro[(η⁶)-1,3,5-trimethylbenzene]ruthenium(II) -   [N-[(1R,2R and     1S,2S)-2-(amino-κN)-1,2-diphenylethyl]-p-tolylsulphonamidato-κN]chloro[(η⁶)-benzene]ruthenium(II) -   [N-[(1R,2R and     1S,2S)-2-(amino-κN)-1,2-diphenylethyl]-o-tolylsulphonamidato-κN]chloro[(η⁶)-benzene]ruthenium(II) -   [N-[(1R,2R and     1S,2S)-2-(amino-κN)-1,2-diphenylethyl]-m-tolylsulphonamidato-κN]chloro[(η⁶)-benzene]ruthenium(II) -   [N-[(1R,2R and     1S,2S)-2-(amino-κN)-1,2-diphenylethyl]-phenylsulphonamidato-κN]chloro[(η⁶)-benzene]ruthenium(II) -   [N-[(1R,2R and     1S,2S)-2-(amino-κN)-1,2-diphenylethyl]-4-ethylphenylsulphonamidato-κN]chloro[(η⁶)-benzene]ruthenium(II) -   [N-[(1R,2R and     1S,2S)-2-(amino-κN)-1,2-diphenylethyl]-3-ethylphenylsulphonamidato-κN]chloro[(η⁶)-benzene]ruthenium(II) -   [N-[(1R,2R and     1S,2S)-2-(amino-κN)-1,2-diphenylethyl]-2-ethylphenylsulphonamidato-κN]chloro[(η⁶)-benzene]ruthenium(II) -   [N-[(1R,2R and     1S,2S)-2-(amino-κN)-1,2-diphenylethyl]-2,4,6-trimethylphenylsulphonamidato-κN]chloro[(η⁶)-benzene]ruthenium(II) -   [N-[(1R,2R and     1S,2S)-2-(amino-κN)-1,2-diphenylethyl]-2,4,6-triisopropylphenylsulphonamidato-κN]chloro[(η⁶)-benzene]ruthenium(II) -   [N-[(1R,2R and     1S,2S)-2-(amino-κN)-1,2-diphenylethyl]-4-chlorophenylsulphonamidato-κN]chloro[(η⁶)-benzene]ruthenium(II) -   [N-[(1R,2R and     1S,2S)-2-(amino-κN)-1,2-diphenylethyl]-3-chlorophenylsulphonamidato-κN]chloro[(η⁶)-benzene]ruthenium(II) -   [N-[(1R,2R and     1S,2S)-2-(amino-κN)-1,2-diphenylethyl]-2-chlorophenylsulphonamidato-κN]chloro[(η⁶)-benzene]ruthenium(II) -   [N-[(1R,2R and     1S,2S)-2-(amino-κN)-1,2-diphenylethyl]-4-fluorophenylsulphonamidato-κN]chloro[(η⁶)-benzene]ruthenium(II) -   [N-[(1R,2R and     1S,2S)-2-(amino-κN)-1,2-diphenylethyl]-3-fluorophenylsulphonamidato-κN]chloro[(η⁶)-benzene]ruthenium(II) -   [N-[(1R,2R and     1S,2S)-2-(amino-κN)-1,2-diphenylethyl]-2-fluorophenylsulphonamidato-κN]chloro[(η⁶)-benzene]ruthenium(II) -   [N-[(1R,2R and     1S,2S)-2-(amino-κN)-1,2-diphenylethyl]-4-methoxyphenylsulphonamidato-κN]chloro[(η⁶)-benzene]ruthenium(II) -   [N-[(1R,2R and     1S,2S)-2-(amino-κN)-1,2-diphenylethyl]-3-methoxyphenylsulphonamidato-κN]chloro[(η⁶)-benzene]ruthenium(II) -   [N-[(1R,2R and     1S,2S)-2-(amino-κN)-1,2-diphenylethyl]-2-methoxyphenylsulphonamidato-κN]chloro[(η⁶)-benzene]ruthenium(II)ato-κN]chloro[(η⁶)-benzene]ruthenium(II) -   [N-[(1R,2R and     1S,2S)-2-(amino-κN)-1,2-diphenylethyl]-1-naphthylsulphonamidato-κN]chloro[(η⁶)-benzene]ruthenium(II) -   [N-[(1R,2R and     1S,2S)-2-(amino-κN)-1,2-diphenylethyl]-2-naphthylsulphonamidato-κN]chloro[(η⁶)-benzene]ruthenium(II) -   [N-[(1R,2R and     1S,2S)-2-(amino-κN)-1,2-diphenylethyl]-pentafluorophenylsulphonamidato-κN]chloro[(η⁶)-benzene]ruthenium(II) -   [N-[(1R,2R and     1S,2S)-2-(amino-κN)-1,2-diphenylethyl]-methanesulphonamidato-κN]chloro[(η⁶)-benzene]ruthenium(II) -   [N-[(1R,2R and     1S,2S)-2-(amino-κN)-1,2-diphenylethyl]-trifluoromethanesulphonamidato-κN]chloro[(η⁶)-benzene]ruthenium(II) -   [N-[(1R,2R and     1S,2S)-2-(amino-κN)-cyclohexyl]-p-tolylsulphonamidato-κN]chloro[(η⁶)-benzene]ruthenium(II) -   [N-[(1R,2R and     1S,2S)-2-(amino-κN)-cyclohexyl]-m-tolylsulphonamidato-κN]chloro[(η⁶)-benzene]ruthenium(II) -   [N-[(1R,2R and     1S,2S)-2-(amino-κN)-cyclohexyl]-phenylsulphonamidato-κN]chloro[(η⁶)-benzene]ruthenium(II) -   [N-[(1R,2R and     1S,2S)-2-(amino-κN)-cyclohexyl]-4-ethylphenylsulphonamidato-κN]chloro[(η⁶)-benzene]ruthenium(II) -   [N-[(1R,2R and     1S,2S)-2-(amino-κN)-cyclohexyl]-2,4,6-trimethylphenylsulphonamidato-κN]chloro[(η⁶)-benzene]ruthenium(II) -   [N-[(1R,2R and     1S,2S)-2-(amino-κN)-cyclohexyl]-4-chlorophenylsulphonamidato-κN]chloro[(η⁶)-benzene]ruthenium(II) -   [N-[(1R,2R and     1S,2S)-2-(amino-κN)-cyclohexyl]-3-chlorophenylsulphonamidato-κN]chloro[(η⁶)-benzene]ruthenium(II) -   [N-[(1R,2R and     1S,2S)-2-(amino-κN)-cyclohexyl]-4-fluorophenylsulphonamidato-κN]chloro[(η⁶)-benzene]ruthenium(II) -   [N-[(1R,2R and     1S,2S)-2-(amino-κN)-cyclohexyl]-3-fluorophenylsulphonamidato-κN]chloro[(η⁶)-benzene]ruthenium(II) -   [N-[(1R,2R and     1S,2S)-2-(amino-κN)-cyclohexyl]-4-methoxyphenylsulphonamidato-κN]chloro[(η⁶)-benzene]ruthenium(II) -   [N-[(1R,2R and     1S,2S)-2-(amino-κN)-cyclohexyl]-3-methoxyphenylsulphonamidato-κN]chloro[(η⁶)-benzene]ruthenium(II) -   [N-[(1R,2R and     1S,2S)-2-(amino-κN)-cyclohexyl]-1-naphthylsulphonamidato-κN]chloro[(η⁶)-benzene]ruthenium(II) -   [N-[(1R,2R and     1S,2S)-2-(amino-κN)-cyclohexyl]-2-naphthylsulphonamidato-κN]chloro[(η⁶)-benzene]ruthenium(II) -   [N-[(1R,2R and     1S,2S)-2-(amino-κN)-cyclohexyl]-methanesulphonamidato-κN]chloro[(η⁶)-benzene]ruthenium(II) -   [N-[(1R,2R and     1S,2S)-2-(amino-κN)-cyclohexyl]-trifluoromethanesulphonamidato-κN]chloro[(η⁶)-benzene]ruthenium(II) -   [N-[(1R,2R and     1S,2S)-2-(amino-κN)-cyclohexyl]-p-tolylsulphonamidato-κN]chloro[(η⁶)-cumene]ruthenium(II) -   [N-[(1R,2R and     1S,2S)-2-(amino-κN)-cyclohexyl]-m-tolylsulphonamidato-κN]chloro[(η⁶)-cumene]ruthenium(II) -   [N-[(1R,2R and     1S,2S)-2-(amino-κN)-cyclohexyl]-phenylsulphonamidato-κN]chloro[(η⁶)-cumene]ruthenium(II) -   [N-[(1R,2R and     1S,2S)-2-(amino-κN)-cyclohexyl]-4-ethylphenylsulphonamidato-κN]chloro[(η⁶)-cumene]ruthenium(II) -   [N-[(1R,2R and     1S,2S)-2-(amino-κN)-cyclohexyl]-2,4,6-trimethylphenylsulphonamidato-κN]chloro[(η⁶)-cumene]ruthenium(II) -   [N-[(1R,2R and     1S,2S)-2-(amino-κN)-cyclohexyl]-4-chlorophenylsulphonamidato-κN]chloro[(η⁶)-cumene]ruthenium(II) -   [N-[(1R,2R and     1S,2S)-2-(amino-κN)-cyclohexyl]-3-chlorophenylsulphonamidato-κN]chloro[(η⁶)-cumene]ruthenium(II) -   [N-[(1R,2R and     1S,2S)-2-(amino-κN)-cyclohexyl]-4-fluorophenylsulphonamidato-κN]chloro[(η⁶)-cumene]ruthenium(II) -   [N-[(1R,2R and     1S,2S)-2-(amino-κN)-cyclohexyl]-3-fluorophenylsulphonamidato-κN]chloro[(η⁶)-cumene]ruthenium(II) -   [N-[(1R,2R and     1S,2S)-2-(amino-κN)-cyclohexyl]-4-methoxyphenylsulphonamidato-κN]chloro[(η⁶)-cumene]ruthenium(II) -   [N-[(1R,2R and     1S,2S)-2-(amino-κN)-cyclohexyl]-3-methoxyphenylsulphonamidato-κN]chloro[(η⁶)-cumene]ruthenium(II) -   [N-[(1R,2R and     1S,2S)-2-(amino-κN)-cyclohexyl]-1-naphthylsulphonamidato-κN]chloro[(η⁶)-cumene]ruthenium(II) -   [N-[(1R,2R and     1S,2S)-2-(amino-κN)-cyclohexyl]-2-naphthylsulphonamidato-κN]chloro[(η⁶)-cumene]ruthenium(II) -   [N-[(1R,2R and     1S,2S)-2-(amino-κN)-cyclohexyl]-methanesulphonamidato-κN]chloro[(η⁶)-cumene]ruthenium(II) -   [N-[(1R,2R and     1S,2S)-2-(amino-κN)-cyclohexyl]-trifluoromethanesulphonamidato-κN]chloro[(η⁶)-cumene]ruthenium(II) -   [N-[(1R,2R and     1S,2S)-2-(amino-κN)-cyclohexyl]-p-tolylsulphonamidato-κN]chloro[(η⁶)-1,3,5-trimethylbenzene]ruthenium(II) -   [N-[(1R,2R and     1S,2S)-2-(amino-κN)-cyclohexyl]-m-tolylsulphonamidato-κN]chloro[(η⁶)-1,3,5-trimethylbenzene]ruthenium(II) -   [N-[(1R,2R and     1S,2S)-2-(amino-κN)-cyclohexyl]-phenylsulphonamidato-κN]chloro[(η⁶)-1,3,5-trimethylbenzene]ruthenium(II) -   [N-[(1R,2R and     1S,2S)-2-(amino-κN)-cyclohexyl]-4-ethylphenylsulphonamidato-κN]chloro[(η⁶)-1,3,5-trimethylbenzene]ruthenium(II) -   [N-[(1R,2R and     1S,2S)-2-(amino-κN)-cyclohexyl]-2,4,6-trimethylphenylsulphonamidato-κN]chloro[(η⁶)-1,3,5-trimethylbenzene]ruthenium(II) -   [N-[(1R,2R and     1S,2S)-2-(amino-κN)-cyclohexyl]-4-chlorophenylsulphonamidato-κN]chloro[(η⁶)-1,3,5-trimethylbenzene]ruthenium(II) -   [N-[(1R,2R and     1S,2S)-2-(amino-κN)-cyclohexyl]-3-chlorophenylsulphonamidato-κN]chloro[(η⁶)-1,3,5-trimethylbenzene]ruthenium(II) -   [N-[(1R,2R and     1S,2S)-2-(amino-κN)-cyclohexyl]-4-fluorophenylsulphonamidato-κN]chloro[(η⁶)-1,3,5-trimethylbenzene]ruthenium(II) -   [N-[(1R,2R and     1S,2S)-2-(amino-κN)-cyclohexyl]-3-fluorophenylsulphonamidato-κN]chloro[(η⁶)-1,3,5-trimethylbenzene]ruthenium(II) -   [N-[(1R,2R and     1S,2S)-2-(amino-κN)-cyclohexyl]-4-methoxyphenylsulphonamidato-κN]chloro[(η⁶)-1,3,5-trimethylbenzene]ruthenium(II) -   [N-[(1R,2R and     1S,2S)-2-(amino-κN)-cyclohexyl]-3-methoxyphenylsulphonamidato-κN]chloro[(η⁶)-1,3,5-trimethylbenzene]ruthenium(II) -   [N-[(1R,2R and     1S,2S)-2-(amino-κN)-cyclohexyl]-1-naphthylsulphonamidato-κN]chloro[(η⁶)-1,3,5-trimethylbenzene]ruthenium(II) -   [N-[(1R,2R and     1S,2S)-2-(amino-κN)-cyclohexyl]-2-naphthylsulphonamidato-κN]chloro[(η⁶)-1,3,5-trimethylbenzene]ruthenium(II) -   [N-[(1R,2R and     1S,2S)-2-(amino-κN)-cyclohexyl]-methanesulphonamidato-κN]chloro[(η⁶)-1,3,5-trimethylbenzene]ruthenium(II)     and -   [N-[(1R,2R and     1S,2S)-2-(amino-κN)-cyclohexyl]-trifluoromethanesulphonamidato-κN]chloro[(η⁶)-1,3,5-trimethylbenzene]ruthenium(II).

Particularly preferred catalysts for step a) are those which comprise ruthenium complexes which are obtainable by reacting S,S- or R,R-N-p-toluenesulphonyl-1,2-diphenylethylenediamine and (cumene)dichlororuthenium dimer.

In ii), operation is effected in the presence of at least one amine, preferably one amine, at least some of which is present in protonated form.

Also formic acid, formates or mixtures thereof are used for ii).

Preference is given to using mixtures of formic acid with amines. In this way, the corresponding ammonium formates are at least partially formed which can be used in a similar manner.

Useful amines are in particular those of the formula (XV) NR¹⁰R¹¹R¹²   (XV) where

R¹⁰, R¹¹ and R¹² are each independently hydrogen, C₁-C₈-alkyl or benzyl.

Particularly preferred amines are ammonia and those of the formula (XV) where R¹⁰, R¹¹ and R¹² are each independently C₁-C₈-alkyl or benzyl.

Particularly preferred amines are those of the formula (XV) where R¹⁰, R¹¹ and R¹² are each identically ethyl, n-butyl or n-hexyl, although even greater preference is given to the use of triethylamine.

The molar ratio of formic acid to tertiary amine may be, for example, 1:1 to 3:1, and preference is given to a ratio of 1.01:1 to 1.5:1.

The molar ratio of formic acid based on substrate used may be, for example, 1:1 to 3:1, and preference is given to 1:1 to 1.5:1, particular preference to 1.02:1 to 1.1:1.

According to iii), step a) may be carried out in the presence or absence, preferably in the presence, of organic solvents.

Examples of suitable organic solvents include:

-   amides, for example dimethylformamide, N-methylpyrrolidinone,     optionally halogenated aliphatic or araliphatic solvents having up     to 16 carbon atoms, for example toluene, o-, m- and p-xylene,     chloroform, dichloromethane, chlorobenzene, the isomeric     dichlorobenzenes, fluorobenzene, nitriles, for example acetonitrile,     benzonitrile, dimethyl sulphoxide or mixtures thereof.

Preferred solvents are acetonitrile, N-methylpyrrolidinone, chloroform, dichloromethane, chlorobenzene, the isomeric dichlorobenzenes, fluorobenzene or mixtures thereof, and particular preference is given to dichloromethane, acetonitrile, N-methylpyrrolidinone or mixtures thereof.

The reaction temperature may be, for example, −10 to 150° C., and preference is given to 20 to 100° C., particular preference to 20 to 80° C.

The reaction times are, for example, between 0.5 h and 48 h, preferably between 6 and 24 h.

The molar amount of ruthenium may be, for example, 0.01 to 1.0 mol %, based on the substrate used, and preference is given to 0.02 to 0.2 mol %, very particular preference to 0.02 to 0.1 mol %.

It is advantageous, although not obligatory, to carry out the reaction in a substantially oxygen-free atmosphere. Substantially oxygen-free means, for example, a content of 0 to 1% by volume, preferably 0 to 0.1% by volume, of oxygen.

The reaction may be accelerated by removing carbon dioxide which is released during the reaction. Advantageous, and therefore encompassed by the invention, is intensive stirring of the reaction mixture at an average stirrer speed of, for example, 100 to 3000 min⁻¹, preferably 500 to 1500 min⁻¹. Alternatively, or supplementarily thereto, the removal of carbon dioxide may be supported by passing an inert gas stream through or over the reaction mixture. Examples of suitable gases include nitrogen, noble gases, for example argon, or mixtures thereof.

A particularly preferred embodiment of step a) is described hereinbelow, although without imposing any limitation.

In a stirred tank, a 1:1 mixture (molar) of formic acid and triethylamine is prepared by simple mixing and compounds of the formula (II) or compounds of the formula (IV) are added in equimolar amounts or in a slight deficiency to this biphasic mixture. Depending on the solubility of the substrate, an amount of an organic solvent is added. The mixture is inertized by passing through nitrogen and the mixture is heated to the desired reaction temperature with vigorous stirring.

The catalyst is added to this mixture as solution in dichloromethane in molar ratios relative to the substrate of, for example, 1:500 to 1:5000, and the reaction mixture is stirred for the desired time. The conversion is followed chromatographically.

The reaction mixture may subsequently be worked up by processes known to those skilled in the art. It has proven advantageous to work up the reaction mixture by adding solvents and dilute aqueous hydrochloric acid or water. After phase separation, the product may be isolated in a manner known per se from the organic phase either distillatively or by a suitable crystallization process.

In step a), enantiomerically enriched compounds of the formulae (III) or (V) are obtained with the definitions and areas of preference specified above.

Depending on the choice of the configuration of the ligands, the S- or R-configured products are obtainable, and the configuration information relates to the carbon atom adjacent to the Ar radical.

The compounds of the formulae (III) or (V) may be isolated or further reacted directly. For intermediate isolation, the reaction mixture may be separated, for example, between water and an organic solvent of low water miscibility, and the desired product transferred to the organic phase. After the removal of the organic solvent, a crude product is obtained which may be purified, for example, by crystallization or distillation.

When compounds of the formula (II) have been used for step a), enantiomerically enriched compounds of the formula (III) are obtained which are reacted in step b) with amines of the formula (VI) and having the definitions and areas of preference specified there.

This may be effected, for example, in such a way that the enantiomerically enriched compounds of the formula (III) are reacted with the amines of the formula (VI), optionally in a solvent. An overview of the synthesis of carboxamides from carboxylic acids, carboxylic esters, carboxylic anhydrides and other carboxamides can be found in Houben-Weyl, 4th edition, volume E 5, 941-1010.

In the case of liquid and gaseous amines, the use of solutions of the amines is suitable. For example, in the case of methylamine, solutions of methylamine in water, methanol or in ethanol may advantageously be used for the reaction of carboxylic esters of the formula (III). For the conversion of free carboxylic acids of the formula (III) to the amides of the formula (V), examples of suitable reactions are those of amines of the general formula (VI) in the presence of coupling reagents such as 2-halopyridinium or -1,3-thiazolium salts, or in the presence of acidic cation exchangers.

It is also possible to convert a compound of the formula (V) to a preferred compound of the formula (V). This may be effected, for example, by transamidation, N-alkylation or N-dealkylation.

In step b), enantiomerically enriched compounds of the formula (V) are then obtained from enantiomerically enriched compounds of the formula (III).

The scope of the invention also encompasses the following compounds of the formula (V):

-   (S)-3-Hydroxy-3-(2-thiophen-yl)-N-methylpropionamide,     (R)-3-hydroxy-3-(2-thiophen-yl)-N-methylpropionamide, and any     desired mixtures of these compounds, for example the racemate.

Particular mention is made of (S)-3-hydroxy-3-(2-thiophen-yl)-N-methylpropionamide.

The enantiomerically enriched compounds of the formula (V) may then be reduced to the enantiomerically enriched compounds of the formula (I). The reduction of carboxamides to the corresponding amines is known in principle and illustrated by way of summary in Houben Weyl, “Methoden der Organischen Chemie”, 4th edition, volume E 16 d, 987-1003.

Preference is given to the reaction of compounds of the formula (V) with complex boron or aluminium hydrides, for example lithium aluminium hydride, Red-Al® (sodium bis(2-methoxyethoxy)dihydroaluminate) or sodium borohydride.

Particular preference is given to the reaction of compounds of the formula (V) with lithium aluminium hydride.

Step c) is preferably carried out at temperatures in the range from 0 to 150° C., more preferably in the range from 50 to 110° C. Customarily, the reductions are carried out in ethers as solvents, preferably in cyclic ethers such as tetrahydrofuran or dioxane, or the reductions with Red-Al® can equally be carried out in toluene as solvent.

In the manner according to the invention, the enantiomerically enriched compounds of the formula (I)

where

Ar, R¹ and R² each have the definitions and areas of preference specified above.

Individual compounds of the formula (I) include:

-   (1S)-3-(methylamino)-1-(2-thiophen-yl)-1-propanol,     (1R)-3-(methylamino)-1-(2-thiophen-yl)-1-propanol,     (1S)-3-(dimethylamino)-1-(2-thiophen-yl)-1-propanol,     (1R)-3-(dimethylamino)-1-(2-thiophen-yl)-1-propanol,     (1S)-3-(methylamino)-1-(phenyl)-1-propanol,     (1R)-3-(methylamino)-1-(phenyl)-1-propanol,     (1S)-3-(methylamino)-1-(4-tolyl)-1-propanol and     (1R)-3-(methylamino)-1-(4-tolyl)-1-propanol.

The enantiomerically enriched compounds of the formula (I) which can be prepared according to the invention are suitable in particular for preparing enantiomerically enriched compounds of the formula (XVI) aryl-CH(OR¹⁰)—CH₂—CH₂NR¹R²   (XVI)

-   where aryl, R¹ and R² each have the definition and areas of     preference specified under the formula (I) and -   R¹⁰ is phenyl or naphthyl which may be not at all, singly or     multiply substituted by substituents which are each independently     selected from the group of cyano, CO—(C₁-C₁₂-alkyl),     O—(C₁-C₁₂-alkyl), (C₁-C₁₂-alkyl), fluorine, chlorine, bromine,     C₁-C₁₂-fluoroalkyl where fluoroalkyl is a singly, multiply or fully     fluorine-substituted alkyl radical.

R¹⁰ is preferably naphthyl.

Preferred compounds of the formula (XVI) are:

-   (S)-N-methyl-3-(1-naphthalenyloxy)-3-(2-thienyl)propylamine and     (R)-N-methyl-3-(1-naphthalenyloxy)-3-(2-thienyl)propylamine and     salts of both and also     (S)-Nmethyl-3-(4-trifluoromethylphenyloxy)-3-(2-phenyl)propylamine     and     (R)-N-methyl-3-(4-trifluoromethylphenyloxy)-3-(2-phenyl)propylamine     and also mixtures of both (e.g. the racemate) and their salts, and     also (S)-N-methyl-3-(2-tolyloxy)-3-(2-phenyl)propylamine and     (R)-N-methyl-3-(2-tolyloxy)-3-(2-phenyl)propylamine and also     mixtures of both (e.g. the racemate) and their salts, although     particular preference is given to     (S)-N-methyl-3-(1-naphthalenyloxy)-3-(2-thienyl)propylamine.

The scope of the invention therefore also encompasses a process which, as step

-   d) encompasses the reaction of compounds of the formula (I) with     compounds of the formula (XVII) in the presence of a base.

In formula (XVII) R¹⁰-Hal  (XVII)

R¹⁰ has the definition and areas of preference specified under the formula (XVI) and Hal is fluorine, chlorine, bromine or iodine, preferably fluorine.

The compounds of the formula (XVII) used are preferably 1-fluoronaphthalene and 4-chlorobenzotrifluoride.

Useful bases are those which can at least partially deprotonate the compounds of the formula (I) at the alcohol function.

Preferred bases are alkali metal hydroxides and hydrides, for example sodium hydride, optionally with the addition of potassium benzoate or potassium acetate, as described in U.S. Pat. No. 5,362,886, sodium hydroxide and potassium hydroxide.

The compounds of the formulae (I), (V) and (XVI) are suitable in particular for preparing pharmaceuticals, such as preferably serotonin or noradrenalin takeup inhibitors.

The process according to the invention has the advantage that it is possible, starting from reactants which are easily obtainable, to synthesize enantiomerically enriched 1-aryl-3-aminopropanols of the formula (I) and their subsequent products in high overall yields, high enantiomeric excesses and high purities on the industrial scale.

EXAMPLES Example 1

In a 2 l flask, 180.8 g of sodium methoxide and 1500 ml of toluene were heated to 100° C. and a solution of 257 g of 2-acetylthiophene in 510 ml of dimethyl carbonate was then added dropwise within 4 hours. The methanol formed in the reaction was distilled off as an azeotrope. In a 4 l flask, 120 ml of conc. sulphuric acid in 900 g of ice was initially charged and the cooled reaction mixture was added in such a way that 40° C. was not exceeded. Stirring was continued and the pH was adjusted to pH 1. The phases were separated and the organic phase was extracted three times with aqueous sodium sulphate solution and then concentrated under reduced pressure. The vacuum distillation of the crude product delivered 278 g of methyl β-oxo-(2-thiophene)propionate as a transparent, light yellow liquid (98% pure by GC, 74% of theory).

Example 2 Methyl (3S)-3-hydroxy-3-(2-thienyl)propanoate

In a Schlenk vessel, the catalyst solution is prepared by weighing 314 mg (2.03 equiv.) of S,S-TsDPEN and 263 mg of [(cumene)RuCl₂]₂ in 10 ml of CH₂Cl₂ and also admixing with 0.3 ml (2 equiv.) of Et₃N and stirring this mixture at room temperature for 15 min.

In a 1 l multinecked flask equipped with a sparging stirrer, reflux condenser and internal thermometer, an HCOOH/Et₃N mixture (molar ratio 1:1) is prepared by gradually adding 41 ml of HCOOH dropwise within 20 min to 152 ml of Et₃N with stirring and ice cooling. 190 g of methyl 2-oxo-3-(2-thienyl)propionate are added to this biphasic mixture, the homogeneous yellow solution is admixed with 0.1 l of dichloromethane and the entire mixture is degassed by passing through argon for 20 min. It is heated to 36° C. and the dark red catalyst solution is added all at once to the reaction mixture with vigorous stirring. Stirring is effected at 800 rpm while passing argon through the reaction mixture for 14 h.

After diluting with 0.3 l of 1N HCl and 0.3 l of CH₂Cl₂ and phase separation, the H₂O phase is extracted 2× more with CH₂Cl₂, the combined organic phases are washed with 150 ml of NaCl solution, dried over MgSO₄, filtered and the solvent is removed. The crude product is used without purification in the next stage 100% conversion.

The conversion and enantiomer analysis were effected by gas chromatography on an HP gas chromatograph using an IVADEX capillary column (12.5 m, 0.3 μm layer thickness using individual temperature programmes).

¹H NMR (dl-chloroform, 400 MHz): δ=7.23 (m, 1H, Ar—H), 6.95 (m, 2H, Ar—H), 5.36 (dd, 1H, CHOH), 3.71 (s, 3H, OCH₃), 2.86 (m, 2H, CHH) ppm.

¹³C NMR (dl-chloroform, 100 MHz): δ=185.3 (C═O), 146.8 (C, Ar), 127.1 (CH, Ar), 125.3 (CH, Ar), 124.1 (CH, Ar), 66.9 (CHOH), 52.4 (CH3), 43.5 (CH2) ppm. Chiral GC: 14.05, 14.41 min. ee=98.2%.

Example 3

115 g of methyl (3S)-3-hydroxy-3-(2-thienyl)propanoate are initially charged and admixed with 618 ml of a 2 molar methanolic methylamine solution. This mixture is stirred at 60° C. for 4 h, cooled and then concentrated under reduced pressure. In this way, 118 g of N-methyl-(3S)-3-hydroxy-3-(2-thienyl)propanamide (purity 86%; 88% of theory) are obtained. The crude product may be used in the next stage or else recrystallized from methylene chloride and hexane. This delivered 93 g of N-methyl-(3S)-3-hydroxy-3-(2-thienyl)propanamide (76% of theory) as white crystals. As an alternative, the purification may also be done by distillation.

The conversion and enantiomer analysis were effected by gas chromatography on an HP gas chromatograph using an IVADEX capillary column (12.5 m, 0.3 μm layer thickness using individual temperature programmes).

Example 4

1728 ml of dry tetrahydrofuran are initially charged with 52 g of lithium aluminium hydride and heated to reflux. At the same time, dropwise addition of 86.4 g of N-methyl-(3S)-3-hydroxy-3-(2-thienyl)propanamide dissolved in 692 g of tetrahydrofuran is commenced. Once dropwise addition is complete, stirring is continued under reflux overnight. The reaction mixture is then cooled to room temperature and 1037 ml of water are cautiously added dropwise. 173 ml of a 10% sodium hydroxide solution were then added dropwise and the solution was filtered. The solvent was removed under reduced pressure. The crude solution was admixed with 346 ml of 1 N sodium hydroxide solution and extracted 3 times with 345 ml of toluene each time. The organic phases are combined and the volatile constituents are removed under reduced pressure to obtain 76 g of (1S)-3-(methylamino)-1-(2-thienyl)-1-propanol (84% purity, 80% of theory). 

1. A 3-hydroxy-3-(2-thienyl)propionamide of the formula: Ar—CH(OH)—CH₂—CO—NR¹R² wherein Ar represents 2-thiophenyl, which is optionally monosubstituted or polysubstituted by fluoro, nitro, hydroxyl, C₁₋₁₂-alkyl, C₁₋₁₂-haloalkyl, C₅₋₁₄-aryl and C₁₋₈-alkoxy; and R¹ and R² are each independently hydrogen, C₁₋₂₀-alkyl, C₄₋₁₄-aryl or C₅₋₁₅-arylalkyl.
 2. A method for preparing an optically active 3-amino-1-(2-thienyl)-1-propanol of the formula: Ar—CH(OH)—CH₂—CH₂—NR¹R² wherein Ar represents 2-thiophenyl, which is optionally monosubstituted or polysubstituted by fluoro, nitro, hydroxyl, C₁₋₁₂-alkyl, C₁₋₁₂-haloalkyl, C₅₋₁₄-aryl and C₁₋₈-alkoxy; and R¹ and R² are each independently hydrogen, C₁₋₂₀-alkyl, C₄₋₁₄-aryl or C₅₋₁₅-arylalkyl; comprising reducing a compound of the formula: Ar—CH(OH)—CH₂—CO—NR¹R² wherein Ar, R¹ and R² are as defined above.
 3. The method according to claim 2, wherein the reducing is carried out in the presence of an aluminum hydride reducing agent.
 4. The method according to claim 3, wherein the aluminum hydride reducing agent is lithium aluminium hydride.
 5. The method according to claim 3, wherein the reducing is carried out in the presence of a boron hydride reducing agent.
 6. The method according to claim 5, wherein the boron hydride reducing agent is sodium borohydride.
 7. The method according to claim 2, which comprises dilution of the product with water. 